1) Field of the Invention
The present invention relates to a technique for performing a mesh dividing process to divide an analytical target model provided as three-dimensional CAD (Computer Aided Design) data into cuboids (shaped like a hexahedron; actually shaped like a rectangular solid) for a numerical analysis.
2) Description of the Related Art
In general, when performing a numerical analysis such as a structural analysis, mechanism analysis, heat-transfer analysis, fluid analysis, thermal-fluid analysis, electromagnetic-field analysis, magnetic-field analysis, or the like using a computer, the numerical analysis is efficiently performed by producing cuboids (basic elements for the numerical analysis; generally referred to mesh elements or grid elements) shaped like a rectangular solid through dividing a target for the numerical analysis, by obtaining characteristic values representing the characteristic of each of the cuboids, and by approximating the target for the numerical analysis at a group of the basic elements (see Patent References 1 to 4 listed below).
In recent years, along with size and weight reductions of electronic devices as computer peripheral equipment, design of structures for appropriately controlling the behavior of heat generated by the electronic devices (e.g. MO (Magneto Optical disk) drives, printers, notebook-sized personal computers, servers, mobile telephones, etc.) has been desired, hence it has been required to accurately analyze the behavior of heat on complicated structures in the electronic devices. For this reason, software for thermal-fluid analysis has been developed as a tool for analyzing the behavior of heat through a computer, and when a numerical analysis is performed with the software, the data divided into cuboids described above is used.
On the other hand, in recent years, automatic conversion software has also been developed, which converts three-dimensional CAD data (geometric data or three-dimensional solid model data) obtained by a CAD system (e.g. Pro/E, I-DEAS, Parasolid, AutoCAD, VPS, or the like) into cuboid data used for numerical analyses in various software.
In the automatic conversion software, a default value previously set in an initial file is generally used as a maximum number of cuboids which defines the upper limit of the number of division of cuboids. Further, the number of mesh-division in the three directions (X-direction, Y-direction, and Z-direction) are independently designated, and division of an analytical target model is performed so that an actual number of cuboids does not exceed the maximum number of cuboids (default value).
In case that the maximum number of cuboids is smaller, the number of cuboids obtained by dividing the analytical target model is also smaller; thereby the analytical processing speed becomes higher but the analytical accuracy decreases. On the contrary, in case that the maximum number of cuboids is larger, the number of cuboids obtained by dividing the analytical target model is also larger, thereby the analytical accuracy is more improved but the analytical processing speed becomes lower. Since the analytical processing speed and the analytical accuracy are heavily affected by complexity of the structure of the analytical target model, in order that the user obtains a desired analytical processing speed and analytical accuracy it is preferable to use not the fixed default value but the optimum maximum number of cuboids corresponding to the complexity of the structure of the analytical target model.
However, under the present circumstances, if the user takes no action, the default value is used as the maximum number of cuboids. For this reason, in order to obtain a desired analytical processing speed and analytical accuracy, conventionally the user needs to modify or change the definition or setting of the maximum number of cuboids when starting the system. In this case, the user appropriately designates a maximum number of cuboids corresponding to the analytical target model, or modifies the maximum number of cuboids once or several times, and actually performs a mesh dividing process to decide the optimum maximum number of cuboids based on the result of the destination or modification.
[Patent Reference 1] Japanese Patent Application Laid-Open NO. HEI10-255077
[Patent Reference 2] Japanese Patent Publication NO. 2657301
[Patent Reference 3] Japanese Patent Publication NO. 3132336
[Patent Reference 4] Japanese Patent Application Laid-Open NO. HEI09-138812
As described above, conventionally, when a maximum number of cuboids is set or modified, the maximum number of cuboids is designated according to the determination of the user, or decided by trial and error. In the former case (in case of user designation), there is a problem in the reliability of the maximum number of cuboids (the problem is whether the maximum number of cuboids is the optimum one corresponding to the analytical target model); in the latter case (in case of trial and error), much time is required to decide the maximum number of cuboids, and hence much time is required for the mesh dividing process.
Furthermore, in a conventional system, a function of estimating a conversion time required for a mesh dividing process for an analytical target model is not provided, the processing time is not clear at all, and the user is not able to ascertain the conversion time at all. In particular, when an analytical target model is a large-scale device, there is a much possibility of a long conversion time, and hence it is desired to make it possible to grasp how long the mesh dividing process needs, that is, how long the waiting time is.